JP3557690B2 - Crystal growth method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for growing a multi-component bulk crystal.
Multi-element bulk materials composed of multiple elements have a high degree of freedom in the lattice constant, and their application fields are widely important as new materials. For example, in a multi-component compound semiconductor, a physical property value such as a band gap can be changed by changing its composition, so that a high-performance semiconductor device can be manufactured.
[0002]
Conventionally, such a semiconductor device has been manufactured by epitaxially growing a multi-component compound semiconductor on a substrate crystal. However, in this case, it is necessary that the lattice constant of the substrate crystal and the lattice constant of the multi-component compound semiconductor layer grown thereon match or are close to each other. If there is a large difference in the lattice constant, various defects are introduced between the substrate crystal and the grown thin film, and the semiconductor device does not operate as designed.
[0003]
By the way, in the case of a compound semiconductor, a binary compound semiconductor such as GaAs or InP is used as the substrate crystal, so that the epitaxial growth film is necessarily limited to those having a value close to the lattice constant of the substrate crystal. That is, the characteristics of the finally obtained semiconductor device are also restricted by these conditions.
[0004]
Therefore, if a multi-component compound semiconductor is used as a substrate, the composition can be changed to change the lattice constant, so that the range of choice of thin films grown thereon can be greatly expanded. As a result, a semiconductor device having better performance than before can be realized. For that purpose, it is necessary to develop a method for producing a multi-component material having an arbitrary composition.
[0005]
However, it is very difficult to make a multi-component large bulk crystal with a uniform composition because the melt composition is different from the crystal composition crystallized from the melt. The present invention can be used to solve this problem.
[0006]
[Prior art]
When making a multi-component bulk material with an arbitrary composition, even if it is grown from a melt having the same composition as the crystal to be grown, the grown material is composed of certain components because the liquid / solid distribution coefficients are different for each component. Is contained more than the melt, and its component is reduced in the melt. Therefore, it is very difficult to form a bulk crystal having a uniform composition.
[0007]
Conventional example 1
As a solution to the above, there is a method of growing by the Czochralski method (pulling method) while replenishing the solute element, that is, a method of growing by the LEC (Liquid Encapsulated Czochralski) method, and a bulk crystal having a fairly uniform composition can be obtained. ing.
[0008]
For example, by using a double crucible method and growing while supplying a GaAs source, highly uniform InGaAs crystals can be obtained.
FIG. 12 shows the LEC method of the double crucible method.
[0009]
In the figure, 11 is an outer crucible, 12 is an inner crucible, 13 is a slit, 14 is a source supply rod, 15 is an In-Ga-As melt, 16 is B₂O₃, 17 is a seed (seed crystal), 18 is a grown InGaAs crystal, and 19 is a GaAs source.
[0010]
Pull-up growth is performed at a constant temperature while replenishing a GaAs source. In this method, since the amount of the melt is large, the composition tends to fluctuate in the melt, and local composition unevenness tends to occur in the pulled bulk crystal.
[0011]
For example, in the growth of InGaAs disclosed in JP-A-4-114991, the GaAs component in the melted InGaAs is depleted as the growth proceeds, so that the InGaAs composition is increased by replenishing the GaAs component during the growth. An InGaAs crystal having a uniform composition of 0.5% was obtained. However, in this case, the amount of the melt decreases because only the depleted components are supplied. Since this causes fluctuations in the growth interface temperature, it is necessary to maintain a constant growth interface temperature by changing the power supplied to the heater or raising the position of the crucible.
[0012]
Conventional example 2
Further, when the GaAs source is directly supplied to the melt, the composition of the melt varies due to melting of the source and fluctuation of contact with the melt surface. This causes the generation of crystal defects. To cope with this, Japanese Patent Application Laid-Open No. 5-213683 discloses a method of providing a partition having a slit (see FIG. 12) between a grown crystal and a source. With this method, the composition fluctuation of the melt near the source is reduced before reaching the growth interface, and the melt at the growth interface maintains the average composition.
[0013]
Conventional example 3
Japanese Patent Application No. 6-303300 discloses a method for simultaneously suppressing the composition fluctuation of the melt and the fluctuation of the melt volume by using a source having the same composition as the crystal to be grown or a plurality of sources having different compositions. A method has been proposed in which the replenishing amount and the replenishing composition are the same as the growing amount and the composition of the grown crystal.
[0014]
As described above, as shown in Conventional Examples 1 to 3, multi-component materials have been produced by adding various devices to the Czochralski method. However, in pulling growth, the amount of melt is large and precise control of the melt volume is possible, but the temperature fluctuation is very large. In other words, even when the heater temperature is kept constant, the temperature at the growth interface fluctuates greatly due to the thermal convection of the melt, and unevenness in the composition remains in the grown crystal. When such a crystal is cut into thin pieces to produce a substrate, the crystal may be broken due to local internal distortion.
[0015]
[Problems to be solved by the invention]
As described above, a subtle fluctuation in the composition of the melt (solution) in the vicinity of the growth interface causes a local fluctuation in the composition in the crystal grown by the LEC method, which remains as an internal strain in the crystal. For this reason, when bulk substrates are cut into thin pieces and polished to produce substrates, cracking and destruction is a serious problem.
[0016]
For this reason, it is necessary to re-grow the crystal once grown by the LEC method as a raw material to make the composition uniform. However, there have been no examples of regrowth of multi-element crystals, and no method has been established. Therefore, the present invention first provides a regrowth method using zone melt.
[0017]
In addition, by applying the zone melt method according to the present invention, a multi-component material having a small composition fluctuation can be grown. Phase composition In having composition x = xl_xlGa_1-xlAs is required. That is, a melt that is in phase equilibrium with the source must be prepared.
[0018]
An object of the present invention is to provide a method for regrowth of a multi-component crystal, to obtain a multi-component bulk crystal having a uniform composition and a small internal strain. It is an object of the present invention to provide a means for producing a melt in phase equilibrium with a crystal during growth.
[0019]
[Means for Solving the Problems]
The solution to the above problems is
1) Regrowth method using zone melt
(1)A melting part made of a multi-component melt maintained at a predetermined liquid-phase growth temperature is connected to a first material crystal of the multi-component system that is in phase equilibrium with the melt at the liquid-phase growth temperature, and the melting is performed. Moving the portion in the direction of the first raw material crystal and using the first raw material crystal as a replenishing raw material to grow the crystal having the first composition on the opposite side of the moving direction of the melting portion. Method, or
(2)A first raw material crystal having a multicomponent first composition;Having a second composition of the multi-component system wherein the liquidus temperature is equal to the solidus temperature of the first compositionConnecting the second raw material crystal,Equal to the solidus temperatureWhile maintaining the liquid phase growth temperature, only the second material crystal is dissolved,TheBy moving the melting section in the direction of the first raw material crystal and using the first raw material crystal as a replenishing raw material,On the opposite side of the moving direction of the melting sectionThe first compositionCrystal withGrowing crystal growth method, or
(3) No.As one raw material crystal, the one or more crystals having an average composition value of the first composition.Is 2The crystal growth method described, or
(Four) ManyThe primary crystal is a group III-V ternary compound, a group II-VI ternary compound,OrSaid 1 which is SiGeOr 2The crystal growth method described, or
(Five) No.The raw material crystal of No. 2 is combined with a seed crystal having the first composition.TheThe first raw material crystal is sandwiched between2The crystal growth method described, or
(6) ConclusionDuring the crystal growth, the temperature distribution in the growth furnaceA high temperature portion higher than the liquid phase growth temperature and lower than the liquidus temperature of the first raw material crystal, a low temperature portion lower than the liquid phase growth temperature, and a temperature having a temperature gradient from the high temperature portion to the low temperature portion. An inclined portion is provided, and the melting portion and the first raw material crystal are arranged in the crystal furnace such that the first raw material crystal is directed to the high temperature portion, and are moved in the direction of the high temperature portion, thereby causing the melting. 3. The method according to 1 or 2, wherein the portion is moved in the direction of the first raw material crystal.Crystal growth method, or
(7) ConclusionIn the crystal growth, the growth furnace is of a pressurized type, or the material disposing part in the growth furnace is pressurized.Or 2The crystal growth method described, or
(8) seedWith crystalsTheThe first raw material crystalTheEnclose the second raw material crystal in an ampoule or put it in a crucibleB _Two O _Three , And put the ampoule or the crucible in the soaking block and move the ampoule or the crucible relative to the soaking block.2The crystal growth method described, or
(9) No.The second raw material crystal is an aggregate of a plurality of crystals, and the average is the same as the composition of the second raw material crystal.2This is achieved by the described crystal growth method.
[0020]
2) In the regrowth method using the zone melt, a method for producing a melt in phase equilibrium with the source crystal during growth is described below.
(Ten)In a crystal growth method for growing a multi-component crystal from a melt,
A first material having the same composition as the multi-component crystal, a second material that dissolves at a temperature lower than the growth temperature, and a seed crystal having a solidus temperature equal to or higher than the growth temperature are brought into contact in this order to grow the material. After being placed in a vessel and heating the growth vessel to form a melted portion formed by melting the second material, the melted portion is maintained at a phase equilibrium temperature with the multicomponent crystal, A crystal growth method in which the melting portion is gradually moved in the direction of the first material, with a phase equilibrium temperature being the growth temperature, or
(11)In the temperature distribution in the growth furnace, a temperature gradient from the growth temperature to the high-temperature portion lower than the liquidus temperature of the first material, the low-temperature portion lower than the growth temperature, and the temperature gradient from the high-temperature portion to the low-temperature portion. The growth vessel is disposed in the growth furnace such that the first material is directed toward the high-temperature section, and is moved toward the high-temperature section. Move in the direction of the material Ten Achieved by the described crystal growth methodIs done.
3) Further, regarding the above methods 1) and 2)
(12) 12. The method according to claim 6, wherein the melting section is moved in the direction of the first material by uniformly lowering the temperature in the growth furnace instead of moving in the direction of the high temperature section. Is achieved by the crystal growth method described above.
[0021]
[Action]
1) Regrowth method using zone melt
The present invention relates to a crystal growth method for regrowing a multi-component crystal to increase the uniformity of the composition and reduce the internal strain. A typical example is a bulk crystal growth of an InGaAs compound semiconductor. Since the same method can be used for other materials, generality is not lost.
[0022]
FIG. 5 shows an InAs-GaAs quasi-binary phase diagram.
In this figure, In of x = 0.95 (point a)_1-xGa_xIn order to obtain As crystals, the melting point composition must be a liquid phase composition (point b) that equilibrates with a solid phase of this composition at the temperature Ta. Thus, the two values are significantly different.
[0023]
For this reason, pull-up growth is performed at a constant temperature (for example, Ta) while replenishing a GaAs source by using the double crucible type LEC method shown in FIG. 12 described above. Fluctuation is likely to occur, and local compositional irregularities are likely to occur in the pulled bulk crystal.
[0024]
For this purpose, it is conceivable to subject the grown bulk crystal to zone melting. However, when the multi-crystal is melted, as shown in FIG. 5, a melt at a point c higher than the solid-liquid equilibrium temperature Ta of this crystal is obtained. Consequently, the crystal grown from this melt has the composition at point d and does not have the original composition at point a. Therefore, when zone melting is performed, the composition becomes non-uniform.
[0025]
On the other hand, in the present invention, by using a crystal having a composition at the point b (or an aggregate of two or more types of crystals having a composition at the point b on average) with a crystal having the composition at the point a, Under the temperature condition where only the crystal having the composition at point a melts and the crystal having the composition at point a does not melt, the crystal grows from the melt having the composition at point b on the seed crystal, and at the same time the point a The crystal having the composition described above is melted at the solid-liquid interface to supply the raw material to the melt. At this time, as shown in FIG. 2, InGaAs (second material crystal) 2 at point b is disposed so as to be sandwiched between InGaAs (first material crystal) 1 at point a and GaAs seed crystal 3. Temperature distribution (T₂<Ta <T₁If the growth is performed while the temperature gradient is shifted downward or the entire crystal is pulled upward, the growth and melt replenishment can be repeated continuously. The same effect as when zone melting is applied to a crystal having a composition of point a, which is a raw material crystal of the above, can be obtained.
[0026]
To keep the crystals, put the whole in a crucible and₂O₃And put in a high-pressure furnace, or may be vacuum-sealed in a quartz tube or the like and placed in a high-pressure furnace.
2) Method for producing a melt in phase equilibrium with the source crystal during growth
In a method for further improving the regrowth method using the zone melt described in the above 1), for convenience of comparing the two, first, a summary of the regrowth method using the zone melt described in the above 1) will be described.
[0027]
In order not to leave uneven fluctuations in the composition in the grown crystal, the crystal once pulled up is used as a material for regrowth, and in order to make the composition uniform, zone melting is applied to the multi-component material. For example, in the case of InGaAs, in the InAs-GaAs quasi-binary phase diagram of FIG. 10 (note: the assignment of the mixed crystal ratio is opposite to that of FIG. 5 for InAs and GaAs)._xGa_1-xIn of composition x = As of As_xsGa_1-xsWhen growing As, the seed crystal GaAs and In_xsGa_1-xsIn which has a composition of x = xl with As_xlGa_1-xlAs is sandwiched between As shown in FIG._xlGa_1-xlAs melts (T = T₂), Source In_xsGa_1-xsAs does not melt (T <T₂) Keep under temperature distribution.
[0028]
By shifting the temperature distribution to the right or shifting the growth vessel to the left,_xsGa_1-xsAs regrowth is performed. In this case, since the width of the zone can be reduced, and replenishment is performed with the growth, the composition fluctuation is smaller than that in the pull-up growth.
[0029]
However, as described above, in this method, every time a crystal having a different composition is grown, an In phase having a liquid phase composition x = xl having a phase equilibrium is formed._xlGa_1-xlAs is required. In other words, if you do not have a melt that is in phase equilibrium with the source, you must start by making the melt for the source.
[0030]
On the other hand, the effect of the present invention, which can produce a melt in phase equilibrium with the source crystal during growth when regrowing to make the composition uniform, is considered to be In._xGa_1-xThe bulk crystal growth of As will be described with reference to FIG. The same method can be used for other materials, so that generality is not lost.
[0031]
In_xsGa_1-xsWhen an As crystal is grown, a GaAs crystal is used as the seed crystal 3, and In is used as the first material 1._xsGa_1-xsAs is used, InAs is prepared as the second material 2 and is used as the first material (source) In._xsGa_1-xsIt is sandwiched between an As crystal and GaAs, which is a seed crystal, and placed in a furnace to perform a process having a temperature distribution shown in FIGS. 6 (A) to 6 (D). In practice, power is supplied to the heater from room temperature and the temperature is gradually increased. Then, first, InAs having the lowest melting point is melted at 942 ° C. (B) When the temperature exceeds this temperature, the In_xsGa_1-xsAs or GaAs is partially melted, and (C) melt becomes InGaAs. (D) Finally, the temperature T of the melt part₂In the In shown in the phase diagram of FIG._xlGa_1-xlIt becomes a melt having the composition of As. At this time, In the high temperature part of FIG._xsGa_1-xsBecause it is lower than the melting point of As_,Source In_xsGa_1-xsAs does not melt. Ie_,At this point, the arrangement is exactly the same as that of the multi-material zone melt method described in the above 1), and as shown in the explanation of FIG._xlGa_1-xlWithout preparing As_,This can be made during growth. Therefore_,If the temperature distribution and the crystal are relatively moved in this state,_,A desired crystal having a uniform composition can be grown.
[0032]
【Example】
1) Regrowth method using zone melt
Example 1
Next, In of x = 0.95 In_1-xGa_xAn example in which an As crystal is grown will be described.
[0033]
1 and 2 are explanatory diagrams of a first embodiment of the present invention.
First, by the LEC method shown in FIG._1-xGa_xA bulk single crystal of As and a second raw material crystal 2 In x of x = 0.64_1-xGa_xA bulk polycrystal of As is produced.
[0034]
At this time, x = 0.95 In_1-xGa_xThe growth solution of As was 1170 ° C, and the melt composition was 36% InAs and 64% GaAs.
In of x = 0.64_1-xGa_xThe growth temperature of As was 1005 ° C., and the melt composition was 10% InAs and 90% GaAs.
[0035]
These two raw material crystals 1, 2 were placed together with the GaAs seed crystal 3 in a quartz tube as shown in FIG. This sample was placed in a carbon block 4 as a soaking body as shown in FIG. 1, and the whole was put into a high-pressure furnace in an argon (Ar) atmosphere of 8 atm and heated to 1170 ° C. by an induction heating coil 5. , The second raw material crystal, x = 0.64 In_1-xGa_xOnly As is melted. In this state, growth is performed while pulling up at a speed of 2 mm / h, and In = 0.95_1-xGa_xIt was obtained by regrowing a bulk single crystal of As.
[0036]
The obtained InGaAs bulk crystal has a diameter of 1.5 cmφ, a length of 6 cm, and a carrier concentration of 1.9 × 10 n-type.⁸/ Cm^-3, Resistivity is 8 × 10⁶Ωcm, electron mobility 5010 cm²/ Vs. The half width by X-ray diffraction was 57 seconds or less, indicating that the composition was uniform.
[0037]
As described above, the obtained bulk single crystal of InGaAs had an extremely uniform composition, had almost no internal strain, and was sliced and polished to be used as a high-quality InGaAs substrate.
[0038]
Example 2
FIG. 3 is an explanatory diagram of Embodiment 2 of the present invention.
Similar to the first embodiment, the same first raw material crystal 1 and second raw material crystal 2 are formed by using the LEC method.
[0039]
The two raw material crystals 1, 2 were placed together with the GaAs seed crystal 3 in a quartz tube as shown in the figure, and sealed in a vacuum. This was put into a pressurized zone melt furnace (Ar pressurized at 8 atm) having a temperature distribution as shown in the figure, and the peak temperature (T₃) Is heated to 1170 ° C. or more and 1220 ° C. or less, and the second raw material crystal, In = 0.64, is obtained._1-xGa_xOnly As is melted.
[0040]
In this state, growth is performed while pulling up at a speed of 2 mm / h, and In = 0.95_1-xGa_xIt was obtained by regrowing a bulk single crystal of As.
As a result, an InGaAs single crystal having the same characteristics as in Example 1 was obtained.
[0041]
Example 3
Next, an embodiment in which an aggregate of a plurality of crystals is used as the second raw material crystal and the composition of the second raw material crystal is the same as the average will be described with reference to FIG.
[0042]
FIG. 4 is an explanatory view of Embodiment 3 of the present invention.
The same first raw material crystal 1 is prepared by using the LEC method as in the first embodiment.
This first raw material crystal 1 is combined with a second raw material crystal 2 (2A: GaAs, 2B: InAs) and a GaAs seed crystal 3 so that the ratio of InAs: GaAs becomes 0.36: 0.64. It was placed in a quartz tube and sealed in vacuum. This was placed in a pressurized zone melt furnace (Ar pressure of 8 atm) having the same temperature distribution as in Example 1 as shown in the figure, and only the second raw material crystal was melted by heating in the same manner as in Example 1. Let it.
[0043]
In this state, growth is performed while pulling up at a speed of 2 mm / h, and In = 0.95_1-xGa_xIt was obtained by regrowing a bulk single crystal of As.
As a result, an InGaAs single crystal having the same characteristics as in Example 1 was obtained.
[0044]
In addition to the InGaAs of the embodiment, the present invention is applicable even if the multi-component crystal is a III-V ternary compound, a II-VI ternary compound, or SiGe. Is applicable.
[0045]
Further, in addition to the GaAs of the embodiment, even if the seed crystal is InAs, GaP, InP, InSb, GaSb, Si, SiGe, InGaAs, InGaP, GaAsP, InAsP, InGaSb, ZnSe, HgTe, CdTe, ZnS, etc. The invention is applicable.
[0046]
In the embodiment, a vertical or horizontal furnace may be used as the growth furnace. Then, it is only necessary that the furnace is a pressurized furnace or that the sample disposition portion in the growth furnace is configured to be pressurized.
[0047]
Further, during the crystal growth of the embodiment, an electric current may be passed through the melt to promote the supply of solute elements.
The crystal growth may be performed while rotating the seed crystal and the first raw material crystal in opposite directions. This rotation improves the uniformity of the composition.
[0048]
In the embodiment, the seed crystal, the first raw material crystal, and the second raw material crystal were grown in an ampoule. Instead, the seed crystal was placed in a crucible.₂O₃It may be covered and grown.
[0049]
Further, by repeating the growth of the embodiment a plurality of times, a crystal having a more uniform composition can be obtained.
2) In the regrowth method using the zone melt, a method for producing a melt in phase equilibrium with the source crystal during growth
Example 4
In FIG. 7, a crucible 4 made of pyrogenic boron nitride (PBN) having a diameter of 18 mm is placed in a carbon soaking block 5 having an outer diameter of 120 mm. Here, a vertical growth furnace as shown in the figure was used, and the temperature distribution was made up of a high-temperature section and a subsequent temperature ramp.
[0050]
GaAs seed crystal 3 having a size of 9 mm × 9 mm × 10 mm and In having a size of 9 mm × 9 mm × 20 mm_0.064Ga_0.936As polycrystal (source of first material) 1 is prepared.
The phase equilibrium with this first material is In_0.47Ga_0.53Although it is a crystal having a composition of As, since the composition of InAs is extremely large, it is extremely difficult to produce a crystal having the composition exactly. Therefore, the 1 mm thick In_0.5Ga_0.5As crystal (second material) 2 was placed in crucible 4 sandwiched between source 1 and seed crystal 3. On top of this, B₂O₃, And after evacuation, the reactor was filled with argon (Ar) at 4 atm and heated. At this time, In_0.5Ga_0.5The temperature at the position of As was set to 1150 ° C., which corresponds to xs = 0.064 in the phase diagram of InAs-GaAs (FIG. 10). In addition, the lower In_0.064Ga_0.936The maximum temperature at the position of the As polycrystal is 1190 ° C._0.064Ga_0.936As it is lower than the melting point of As,_0.064Ga_0.936As does not melt alone.
[0051]
Then, it was kept at this position for 2 hours, and it was waited until the zone portion melted and the molten components were sufficiently mixed at this temperature. After that, the temperature of the heater was slowly lowered at 0.1 ° C./h to relatively move the temperature distribution.
[0052]
The crystal thus obtained was cut, polished and etched, and then subjected to photoluminescence (PL) measurement. The PL was measured at 77 K and the spot size of the laser was about 150 μm × 150 μm, and the mixed crystal composition was determined from the PL peak wavelength. As a result, a crystal having an extremely uniform composition was obtained as shown in FIG.
[0053]
Example 5
In FIG. 9, as a first material, In 15 mm in diameter and 30 mm in length produced by conventional pull-up growth is used._0.05Ga_0.95As polycrystal 1_,An InAs polycrystalline wafer 2 having a thickness of 2 mm was used as a second material. In addition, as a seed crystal, In_0.05Ga_0.95As single crystal 3 was grown by the conventional pulling method, but it was only 15 mm in diameter and 5 mm in length.
[0054]
These crystals were placed in a quartz tube 4 as shown in the figure and sealed in a vacuum. This quartz tube was placed in a furnace having a set temperature distribution as shown in a horizontal furnace and the temperature was raised. At this time, the InAs is melted to a thickness of about 4 mm._0.36Ga_0.64As. At this time, the heater power and the position of the quartz tube were adjusted so that both interfaces of the melt became 1170 ° C.
[0055]
In this state, the quartz tube was grown while moving it to the left at 2 mm / h.
In_0.05Ga_0.95A bulk single crystal of As could be regrown.
In thus obtained In_0.05Ga_0.95Example of variation in composition of As bulk single crystal
As in the case of No. 4, the composition was extremely small and the composition was uniform over the entire crystal.
[0056]
In the fourth and fifth embodiments, not only the seed crystal but also at least one of the first material and the second material may be a single crystal.
In Examples 4 and 5, a group III-V compound semiconductor was used as the seed crystal, the first material, or the second material. However, a group II-VI compound semiconductor, or a group IV semiconductor was used. The gist of the invention does not change.
[0057]
Further, in order to eliminate the non-uniformity of heat caused by the heater, the first material and the seed crystal are grown while rotating at a speed of 1 to 20 rpm in the same direction or in the opposite direction, thereby improving the temperature uniformity.
[0058]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the regrowth method of a multi-component crystal | crystallization can be obtained, and a multi-component bulk crystal with a uniform composition and little internal distortion can be obtained.
[0059]
In other words, the present invention is a method in which the growth is performed at a constant temperature, and the replenishment is continuously performed during the growth by using the raw material crystal having the same composition as the grown crystal. Thus, a multi-element bulk crystal having a more uniform composition than the LEC method can be grown in principle. In addition, since the whole crystal can be grown in a high-pressure furnace by placing it in a carbon block as a soaking body, the temperature soaking property is higher than in the LEC method, and the composition fluctuation is further reduced.
[0060]
Also, since the temperature of the melt or solid-liquid interface can be monitored more accurately than the LEC method, it is more effective in homogenizing the composition.
Furthermore, it is easy to introduce an external effect such as energization into the melt, and this is also effective in expanding the means for making the composition uniform.
[0061]
Further, according to the present invention, a melt in phase equilibrium with a source crystal can be produced during growth when a multi-component compound semiconductor crystal is regrown to make the composition uniform, and a melt is separately prepared. No longer needed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram (1) of a first embodiment of the present invention.
FIG. 2 is an explanatory view (2) of the first embodiment of the present invention.
FIG. 3 is an explanatory diagram of a second embodiment of the present invention.
FIG. 4 is an explanatory view of Embodiment 3 of the present invention.
FIG. 5 is a phase diagram of a quasi-binary system of InAs-GaAs.
FIG. 6 is an explanatory view of the principle of the present invention (explanation of an action capable of producing a melt in phase equilibrium with a source crystal during growth).
FIG. 7 is an explanatory view of a fourth embodiment of the present invention.
FIG. 8 is an explanatory diagram of an effect of the fourth embodiment of the present invention.
FIG. 9 is an explanatory view of a fifth embodiment of the present invention.
FIG. 10 is a quasi-binary phase diagram of InAs-GaAs.
FIG. 11 is an explanatory view of the regrowth method of the present invention.
FIG. 12 is an explanatory diagram of LEC by a double crucible method.
[Explanation of symbols]
1 First raw material crystal (first material)
2 Second raw material crystal (second material)
3 seed crystals
4 Growth vessels
5 Carbon soaking body
6 Induction heating coil

Claims (12)

  A melting part made of a multi-component melt maintained at a predetermined liquid-phase growth temperature is connected to a first material crystal of the multi-component system that is in phase equilibrium with the melt at the liquid-phase growth temperature, and the melting is performed. Is moved in the direction of the first raw material crystal, and the first raw material crystal is used as a replenishing raw material to grow the crystal having the first composition on the opposite side of the moving direction of the melting part. Characteristic crystal growth method. A first raw material crystal having a multicomponent first composition and a second raw material crystal having a second composition having a liquidus temperature equal to the solidus temperature of the first composition; And dissolving only the second raw material crystal while maintaining the liquid phase growth temperature equal to the solidus temperature, moving the melting part in the direction of the first raw material crystal, A crystal growth method, wherein a crystal having the first composition is grown on a side opposite to a moving direction of the melting part by using the crystal as a replenishing raw material. 3. The crystal growth method according to claim 1, wherein an average value of a composition of the first raw material crystal is a first composition. The multi-component crystal, III-V group ternary compound, II-VI group ternary compound, or a crystal growth method according to claim 1 or 2 characterized in that the SiGe. The second raw material crystals, crystal growth method according to claim 2, wherein the placing is sandwiched between the seed crystal and the said first material crystal having a first composition. During the crystal growth, the temperature distribution in the growth furnace includes a high-temperature portion higher than the liquid-phase growth temperature and lower than the liquidus temperature of the first raw material crystal, a low-temperature portion lower than the liquid-phase growth temperature, and A temperature gradient section having a temperature gradient from the high temperature section to the low temperature section;
The melting part and the first raw material crystal are arranged in the crystal furnace such that the first raw material crystal is directed to the high temperature part, and are moved in the direction of the high temperature part, so that the melting part is placed in the first raw material crystal. crystal growth method according to claim 1 or 2 wherein moving the raw material crystal direction, characterized in Rukoto. 3. The crystal growth method according to claim 1, wherein the growth furnace is of a pressurized type, or the sample placement portion in the growth furnace is configured of a pressurized type. Or encapsulating the seed crystal and said first source crystal and said second raw material crystals in ampoules, or covered with B ₂ O ₃ were placed in a crucible, enter the ampoule or the crucible in the Hitoshinetsutai block 3. The method according to claim 2 , wherein the ampoule or the crucible is moved relatively to the heat equalizing block. As a raw material crystals of the second, the aggregate of a plurality of crystals, the crystal growth method according to claim 2, characterized in that the same as the composition of the second material crystal as an average. In a crystal growth method for growing a multi-component crystal from a melt,
A first material having the same composition as the multi-component crystal, a second material that dissolves at a temperature lower than the growth temperature, and a seed crystal having a solidus temperature equal to or higher than the growth temperature are brought into contact in this order to grow the material. Placed in a container,
Heating the growth vessel to form a melted portion formed by melting the second material, maintaining the melted portion at a phase equilibrium temperature with the multicomponent crystal,
A crystal growth method, characterized in that the melting portion is gradually moved in the direction of the first material with the phase equilibrium temperature being the growth temperature. In the temperature distribution in the growth furnace, a temperature gradient higher than the growth temperature and lower than the liquidus temperature of the first material, a lower temperature portion lower than the growth temperature, and a temperature gradient from the higher temperature portion to the lower temperature portion. Temperature gradient part,
Disposing the growth vessel in the growth furnace such that the first material is directed toward the high-temperature portion and moving the melted portion toward the first material by moving the melted portion toward the first material; The crystal growth method according to claim 10, wherein: 12. The method according to claim 6 , wherein the melting section is moved in the direction of the first material by uniformly lowering the temperature in the growth furnace instead of moving in the direction of the high temperature section. The crystal growth method according to the above.

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